The error function, denoted as erf(x), is defined mathematically as erf(x) = (2 / sqrt(π)) ∫0..x e^(-t²) dt. It is primarily used in heat transfer and statistics, particularly as the integral of a Gaussian distribution. The error function enhances the expressive power of closed forms by allowing the representation of many nonelementary functions. It frequently appears in the solutions to differential equations, making it a valuable tool in various mathematical applications. Understanding the error function is essential for tackling problems in heat transfer and related fields.